title: Phosphatidylglycerol directs binding and inhibitory action of EIIAGlc protein on the maltose transporter.
abstract: The signal-transducing protein EIIA(Glc) belongs to the phosphoenolpyruvate carbohydrate phosphotransferase system. In its dephosphorylated state, EIIA(Glc) is a negative regulator for several permeases, including the maltose transporter MalFGK2. How EIIA(Glc) is targeted to the membrane, how it interacts with the transporter, and how it inhibits sugar uptake remain obscure. We show here that acidic phospholipids together with the N-terminal tail of EIIA(Glc) are essential for the high affinity binding of the protein to the transporter. Using protein docking prediction and chemical cross-linking, we demonstrate that EIIA(Glc) binds to the MalK dimer, interacting with both the nucleotide-binding and the C-terminal regulatory domains. Dissection of the ATPase cycle reveals that EIIA(Glc) does not affect the binding of ATP but rather inhibits the capacity of MalK to cleave ATP. We propose a mechanism of maltose transport inhibition by this central amphitropic regulatory protein.
authors.affiliation: Department of Biochemistry and Molecular Biology, Life Sciences Institute, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia V6T1Z3, Canada.
authors.forename: Huan
authors.initials: H
authors.lastname: Bao
authors.forename: Franck
authors.initials: F
authors.lastname: Duong
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000037:antagonists & inhibitors* / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism*; D007700:Kinetics; D008958:Models, Molecular; D010715:Phosphatidylglycerols / Q000378:metabolism*; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D017433:Protein Structure, Secondary; D013329:Structure-Activity Relationship
chemical_list: D018528:ATP-Binding Cassette Transporters; D003432:Cross-Linking Reagents; D029968:Escherichia coli Proteins; C489398:MalK protein, E coli; D010715:Phosphatidylglycerols; C032242:crr protein, E coli; C461599:maltose transport system, E coli; D000255:Adenosine Triphosphate; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System
keywords: ABC Transporter; ATPase; Enzyme Kinetics; Lipids; Membrane Proteins; Nanodiscs; Transport